This R-L21 descendant chart represents all currently known Y-SNP descendants of the R-L21 Y-SNP. New descendants of the R-L21 Y-SNP are now being discovered on a weekly basis and this chart has to be constantly updated to include new descendants. Additional testing of existing Y-SNPs may also reveal new connections that were previously unknown between R-L21 SNPs as well. Keeping current with these constant changes and analyzing newly discovered R-L21 Y-SNP descendants takes a significant amount of time, so the descendant chart may be one or two months out of date at times. Additions and corrections of the R-L21 descendant chart is very dependent on the R-L21 community of researchers assisting me with keeping this descendant chart accurate and complete.

As with any genealogical genetic resource, there are major assumptions and this resource is no exception. This descendant chart is limited to only descendants of the R-L21 Y-SNP and will probably never be expanded in scope to include other major Y-SNPs. This descendant chart should not be your only source for testing candidates and should be used in conjunction with the R-L21 SNP predictor tool, the R-L21 Private web site, the Yahoo Group R-L21 Plus project spreadsheet. The R-L21 descendant chart should be reviewed first for possible testing candidates. Once testing candidates are determined from this descendant chart, it is highly recommended that you further analyze these Y-SNP testing candidates by using the R-L21 Y-SNP predictor tool.

If the R-L21 Y-SNP predictor tool recommends a testing Y-SNPs that are not a descendants of your most recent R-L21 Y-SNP, then do not test these Y-SNPs. The R-L21 Y-SNP predictor tool will produce false hits at times and the R-L21 descendant chart is much more reliable. However, using only R-L21 descendant chart exclusively is not recommended as well since the R-L21 SNP predictor tool can reveal the better testing candidates as well as filter out very low odd testing candidates. Unfortunately, the R-L21 SNP predictor tool is limited single fingerprint Y-SNPs which are the more recent Y-SNPs under R-L21. Multiple fingerprint Y-SNPs will probably never be analyzed by the R-L21 SNP predictor tool due to their complexity and the older age of these Y-SNPs. There are currently around ten R-L21 Y-SNPs that have multiple fingerprints and these Y-SNPs are shaded salmon in the highlighted boxes.

The R-L21 descendant chart also shows all redundant Y-SNPs that can be tested as well. The redundant Y-SNPs currently track their parent Y-SNP 100 % at this time. As more submissions are tested for these redundant Y-SNPs, new branches may be discovered. The redundant Y-SNP may be slightly older or slightly younger than current parent of the redundant Y-SNP. The redundant Y-SNP may be proven to be another son of the current parent Y-SNP or the redundant Y-SNP may be discovered to be the father of current parent Y-SNP. Many currently redundant Y-SNPs will eventually become new branches in the R-L21 descendant chart in the future or they could remain redundant Y-SNPs indefinitely. As the number of tests for the redundant Y-SNPs increases, the testing of these Y-SNPs become more speculative and will have increasingly lower odds of becoming new branches in the R-L21 descendant chart. All redundant Y-SNPs are shaded tan in the highlighted boxes and have dash "R" after the Y-SNP number.

In addition to the R-L21 descendant chart and the R-L21 SNP predictor tool, every "single fingerprint" Y-SNP has three additional resources that should be consulted before testing. The R-L21 Private web site has three resources for each "single fingerprint" R-L21 Y-SNP: 1) a detailed analysis of each Y-SNP; 2) a specific list of recommended testing candidates for each Y-SNP; 3) a "DNA Results" spreadsheet for each Y-SNP that includes a summary of known testing candidates that are sorted by probability of testing positive (the higher in the spreadsheet maps to higher odds of testing positive). Since this information is very time consuming to compile, these resources may be several months old at various times. In addition to these resources, the R-L21 Plus Yahoo Group is another excellent source of R-L21 information and has a very expansive spreadsheet of L21 submissions.

R-L21 "private" Y-SNPs are those Y-SNPs that currently do not qualify for inclusion on the ISOGG haplotrees due to the limited scope of those submissions that have tested positive to date. Some of these Y-SNPs are are classified as "private" Y-SNPs merely because of insufficient testing to reveal the true breadth of these Y-SNPs. Over time, many of these "private" Y-SNPs could later be proven broader in scope and could get added to the ISOGG haplotree. Additionally, many R-L21 "private" Y-SNPs currently have no known connection to any other R-L21 Y-SNPs. As new Y-SNPs are discovered and as more testing results of Y-SNPs becomes available, many R-L21 "private" Y-SNPs may later be connected to other R-L21 Y-SNPs as well.

Testing for Y-SNPs should be a top to bottom testing methodology based on the R-L21 descendant chart. You should first examine the R-L21 descendant chart to create a list of possible testing candidates. You should next use the R-L21 SNP predictor tool to check to see if your Y-STR patterns matches one of the existing "single fingerprint" Y-SNPs. If the R-L21 SNP predictor tool returns odds listed as below 20 %, those Y-SNPs should be considered speculative to test. If all the "single fingerprint" Y-SNPs have less than 20 % odds, your next step would be to test the "big five" broad Y-SNPs. Since these five broad Y-SNPs are ancestors of more than half of all R-L21 submissions, these are the best Y-SNPs to test next. These Y-SNPs are Z253, DF21, DF49 (DF23), L513 and Z255. If you test positive for DF21, continue to test Y-SNPS at the next lower level below the positive Y-SNP - testing only those boxes that are "multiple fingerprint" which are shaded in salmon color. If all the broad five Y-SNPs test negative, you continue to test at the next lowest level (except those less than 20 % odds shown by the R-L21 SNP predictor tool).

If you want to help the R-L21 research indirectly, you have several options to enhance the discovery and prediction of newly discovered R-L21 Y-SNPs. First, collecting and updating valid R-L21 submissions is currently very tedious and takes significant time away from analysis. Many surname projects have not created a web site where FTDNA links can be added that dynamically generate the standard FTDNA Y-STR and Y-SNP reports for all submissions that currently belong to the surname project. Please lobby your surname project admins to add this functionality so that the data collection process will consume less time. Also, many useful submissions have not joined the FTDNA R-L21 Plus project and other R-L21 haplogroup projects. Please join these projects and encourage others to join these projects as well. Many good testing candidates are found in Y-Search queries, so upload your submissions to Y-Search and encourage others to upload as well. All Y-SNP prediction is based on a minimum of 67 markers, so encourage those submssions with less than 67 markers to upgrade to 67 markers.

The numbers below each Y-SNP are the number of testing candidates found in the R-L21 Plus spreadsheet as of July 4th, 2012. When the Y-SNP has an asterisk by the Y-SNP name, this means the number represents the number of testing candidates that are predicted to test positive for that Y-SNP but excludes any testing candidates of any descendants of that Y-SNP. For the smaller breadth Y-SNPs, many currently do not have signatures and estimates from my web site were used.

One of my primary reasons for creating this web site (and the associated R-L21 SNP predictor tool) is to reduce the costs associated with unnecessary testing of poor testing candidates. Since this web site should greatly reduce unnecessary testing, donate part of your testing savings to either the R-L21 project or the R-L21 WTY project. These funds will be used for discovery of new Y-SNPs via the FTDNA "Walk the Y" test, testing required Y-SNPs to get Y-SNPs added to the ISOGG haplotree, testing Y-SNPs for specific submissions to determine the breadth of Y-SNPs and testing related Y-SNPs to see how Y-SNPs are connected. Eventually, you will run out of good Y-SNP testing candidates. In addition to donating funds to R-L21 related projects, you should also consider sponsoring other submissions for upgrades to 67 markers or sponsor other submissions for the testing of Y-SNPs that help R-L21 research.